//
//  PYMD5Util.m
//  IHome
//
//  Created by Jim on 2019/10/3.
//  Copyright © 2019 com.zhujizheng. All rights reserved.
//

#import "PYMD5Util.h"
#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonDigest.h>

#define FileHashDefaultChunkSizeForReadingData 1024*8 // 8K

@implementation PYMD5Util

+ (NSString*)getmd5WithString:(NSString *)string
{
    const char* original_str = [string UTF8String];
    unsigned char digist[CC_MD5_DIGEST_LENGTH]; //CC_MD5_DIGEST_LENGTH = 16
    CC_MD5(original_str, (CC_LONG)strlen(original_str), digist);
    NSMutableString* outPutStr = [NSMutableString stringWithCapacity:10];
    for (int i = 0; i < CC_MD5_DIGEST_LENGTH; i++){
        [outPutStr appendFormat:@"%02x", digist[i]];//小写x表示输出的是小写MD5，大写X表示输出的是大写MD5
    }
    return [outPutStr lowercaseString];
}



+ (NSString*)getMD5WithData:(NSData *)data{
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5( data.bytes, (CC_LONG)data.length, digest );
    NSMutableString *output = [NSMutableString stringWithCapacity:CC_MD5_DIGEST_LENGTH * 2];
    for (int i = 0; i < CC_MD5_DIGEST_LENGTH; i++ ) {
        [output appendFormat:@"%02x", digest[i]];
    }
    if (!output) {
        NSLog(@"md5生成失败");
    }
    return output;
}



+ (NSString*)getFileMD5WithPath:(NSString*)path
{
    return (__bridge  NSString *)FileMD5HashCreateWithPath((__bridge CFStringRef)path,FileHashDefaultChunkSizeForReadingData);
}

CFStringRef FileMD5HashCreateWithPath(CFStringRef filePath, size_t chunkSizeForReadingData) {
    // Declare needed variables
    CFStringRef result = NULL;
    CFReadStreamRef readStream = NULL;
    // Get the file URL
    CFURLRef fileURL = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, (CFStringRef)filePath, kCFURLPOSIXPathStyle, (Boolean)false);
    CC_MD5_CTX hashObject;
    bool hasMoreData = true;
    bool didSucceed;
    if (!fileURL) goto done;
    // Create and open the read stream
    readStream = CFReadStreamCreateWithFile(kCFAllocatorDefault, (CFURLRef)fileURL);
    if (!readStream) goto done;
    didSucceed = (bool)CFReadStreamOpen(readStream);
    if (!didSucceed) goto done;
    // Initialize the hash object
    CC_MD5_Init(&hashObject);
    // Make sure chunkSizeForReadingData is valid
    if (!chunkSizeForReadingData) {
        chunkSizeForReadingData = FileHashDefaultChunkSizeForReadingData;
    }
    // Feed the data to the hash object
    while (hasMoreData) {
        uint8_t buffer[chunkSizeForReadingData];
        CFIndex readBytesCount = CFReadStreamRead(readStream, (UInt8 *)buffer, (CFIndex)sizeof(buffer));
        if (readBytesCount == -1)break;
        if (readBytesCount == 0) {
            hasMoreData =false;
            continue;
        }
        CC_MD5_Update(&hashObject,(const void *)buffer,(CC_LONG)readBytesCount);
    }
    // Check if the read operation succeeded
    didSucceed = !hasMoreData;
    // Compute the hash digest
    unsigned char digest[CC_MD5_DIGEST_LENGTH];
    CC_MD5_Final(digest, &hashObject);
    // Abort if the read operation failed
    if (!didSucceed) goto done;
    // Compute the string result
    char hash[2 *sizeof(digest) + 1];
    for (size_t i =0; i < sizeof(digest); ++i) {
        snprintf(hash + (2 * i),3, "%02x", (int)(digest[i]));
    }
    result = CFStringCreateWithCString(kCFAllocatorDefault,  (const char *)hash, kCFStringEncodingUTF8);
done:
    if (readStream) {
        CFReadStreamClose(readStream);
        CFRelease(readStream);
    }
    if (fileURL) {
        CFRelease(fileURL);
    }
    return result;
}

@end
